Ceiling fans are very common household and commercial appliances. Conventional ceiling fans are difficult to install due to the installer having to perform a number of difficult manoeuvres. Installing a conventional ceiling fan usually means the installer standing on a stool or scaffold trying to work overhead with the mechanical and electrical attachments of the motor housing and rotor components of the fan. After the motor housing and rotor are properly positioned, the installer must then attach the fan blades to the fan rotor. This typically means trying to work from the underside of the fan and to fasten the blades and/or blade mounting arms to the motor or rotor by screws with precision. Depending on the number of blades, the same procedure has to be repeated a few times before installation is completed. Such traditional blade fastening method is highly unsatisfactory. It requires the installer great dexterity, patience, efforts and time in order to connect each and every blade to the fan rotor. In countries where labour costs are high, installing a ceiling fan can be very expensive.
It is therefore highly desirable to have the ceiling fan manufacturer pre-assemble the fan blades onto the fan rotor so that a user only needs to simply unpack the fan and hang it up in the ceiling. However, ceiling fans with pre-assembled fan blades take up a lot of space and makes packaging very difficult, if not impossible. The box containing a ceiling fan with its blades fully pre-assembled in a spread out horizontal position is bulky, awkward to handle and expensive to ship. This accounts for one of the main reasons why ceiling fans are still packaged in the conventional manner and leave the blade installation described above to the users.
In view of the foregoing shortcomings, it is advantageous to have a ceiling fan whereby the blades are factory pre-assembled but the fan blades are collapsible so that the fan can be packaged in such a way that it does not become bulky and awkward to transport. Attempts have been made to achieve this objective in the prior art. For example, U.S. Pat. No. 6,213,716 (issued to Bucheretal. on Apr. 10, 2001) teaches a folding fan and packaging materials for shipping such a fan. However, the Bucher et al. design does not provide a fan blade folding mechanism that is secure for the ceiling fan operation. Once unfolded, the blades rest on a horizontal plane position by the restriction of the hinge movement and have to rely on sheer gravity to pull and hold themselves in the horizontal position. When in operation, this creates wobbling and is unsafe to use. Accordingly, it is beneficial to develop a blade spreading assembly such that the blades can be pre-attached to the rotor and operate in a secure fashion and, at the same time, collapsible for easy installation by the user and allows for inexpensive shipping.
It is also advantageous to be able to spread the pre-attached blades or to dislodge the unfolded blades by a single simple step without having the need to use special tools.